Method For Matching Printing Ink Colors

ABSTRACT

Abstract of the Disclosure 
      A system is provided that includes a first computer that can communicate with a second computer.  The second computer sends information to the first computer that includes a desired ink color and optionally includes information of other desired ink properties.  The first computer includes a database of data for predicting color data of ink formulations using a selected ink base color set, a software program for selecting an ink formulation based on data for a desired ink, and a software program for sending information to the second computer to display the color of the selected ink formulation on a color monitor connected to the second computer.  The ink base color set can be selected to provide other desired properties for the ink, such as low cost, light fastness, or chemical resistance.

Detailed Description of the Invention Field of the Invention

The invention generally relates to printing ink manufacturing processes.In particular, the invention concerns an interactive system for colorapproval by communication with remote locations and supplying printinginks to remote locations for printing uniform colors. Background of theInvention

Many companies seek to capitalize on having a national or internationalpresence by promoting to their customers the advantages of a supplierthat can provide a product or service of uniform quality anywhere in thecountry or the world from its network of locations. A national orinternational company may also seek to foster an image of increasedservice and superior research based upon the combined and complementaryefforts of groups separated geographically but working together to meetthe customer’s needs.

One tool that can be effective to portray an international but unifiedmarket presence is the adoption of a uniform look for labeling andproduct literature. While the company that seeks a uniform look has anational or international business, the printing is typically done on alocal scale by different small, independent printers. The labels,product brochures, or other printed articles may then have colorvariations from location to location, or even for different printingruns because of error introduced by subjective color matching methods,by slightly different color standards, by different equipment anddifferent printing conditions, and so on. The colors of printedmaterials can also vary because they are printed by different processes,for example by a lithographic process or by a gravure printing process.Different kinds of printing inks, for example heat-set inks or dryinginks, could also be used, depending upon the particular printer. Suchdifferences in the printed materials detracts from the desired image ofa national or global company with a strong, unified effort.

For these reasons, it would be desirable to have a method of assuringthe closest match in color and quality, regardless of wheregeographically the article is printed. Summary of the Invention

The present invention provides a system that enables the buyer ofprinted materials (“print buyer”) to obtain printed materials that havematching print colors, even when the inks are manufactured at differentlocations and the materials are printed by different printing companiesand at distant locations, and even when the printing is done usingdifferent printing processes.

The present invention further provides a computerized system with remoteaccess capabilities for identifying a desired ink color and aformulation for a matching ink color based upon a given set of availableink base colors. The desired ink color is identified using the spectraldata or other data to define the desired color, an interface forcomparing the color standard with the selected ink color for thecustomer’s approval, an optional procedure for adjusting the ink color(and the formulation for the ink color) based upon input from thecustomer, and optionally a link to a dispensing system having the inkbase colors of the formulation for mixing the color bases of theformulation to make the ink.

In a preferred embodiment, the generated ink formulation is identifiedwith the print buyer code or with a product code for producingadditional ink batches for the same or for another printer who printsmaterials for that print buyer.

In another aspect, the invention provides a method for identifying adesired print color on a computerized system with remote accesscapabilities in which a desired ink color is input to a color matchingprogram, being converted first, if necessary, to the coordinates thatthe color matching program will use. The color matching program uses thedesired color data, and optionally other data such as informationrelating to the type of ink desired, to determine a formulation for acolor-matched ink. The formulation can then be transmittedelectronically to manufacturing equipment where the ink is producedaccording to the generated ink formulation. The computerized systempreferably identifies the input color and the generated ink formulationwith the print buyer so that additional ink batches of identical colorcan be prepared. Brief Description of the Drawings

FIG. 1 is a block diagram of one preferred embodiment of the system ofthe invention;

FIG. 2 is an informational screen that conveys the results of theelectronic color match in one embodiment of the invention;

FIG. 3 is a screen of a graphical user interface in one embodiment ofthe invention; Detailed Description of the Invention

Using the computerized system with remote access capabilities, each ofthe color selection, selection of an ink formula matching the selectedcolor, color match approval, and ink manufacturing components can beremotely located but still controlled to produce printing of uniformquality and color. By “remote” it is meant that a location is located ata different site. The color approval process is carried out by computercommunication. The advantage of the invention, as will be apparent fromthe following description, is that the locations for inputting thedesired color, for matching the desired color to an ink formulation, andfor manufacturing the ink according to that formulation can be locatedin different parts of the world, and yet the system of the invention cancarry out the process from the initial input of the desired colorthrough manufacture of the ink in a day or even in hours.

In one aspect, the process and system of the invention may beillustrated by reference to FIG. 1. In the embodiment shown in FIG. 1, aremote location includes a spectrophotometer 2, a first computer(central processing unit) 4, a color monitor 6 electronically connectedto the computer, and a viewing booth 8. The spectral data of a colorsample of the desired color is obtained using the spectrophotometer 2.The color data for the desired color is input into the computer 4, whichtransmits the data to a second computer 10.

In the illustrated embodiment, the second computer is designated as aserver or host computer, but all that is required is that the first andsecond computers be able to communicate with one another. The inventionis not limited to client-server relationships, and it can readily beseen that other relationships are possible that will allow communicationbetween the first computer and the second computer. The invention thusrelies on a communications system, such as a global communicationnetwork. One such global communication network is the Internet (based onthe Transmission Control Protocol/Internet Protocol, or TCP/IP). Usingsuch communication each printer-customer can view color matchingresults. In a preferred embodiment, the system uses an Internet (i.e.,TCP/IP) graphical user interface for interacting with individual printercustomers, print buyers, packaging designers, and others for whom suchink color matching is desirable. The system also preferably includes asthe second computer an Internet (TCP/IP) second computer or server thatinteracts with the customer via the customer’s first computer or clientinterface. The customer (whether printer, designer, or print buyer) caninput the ink color and type and/or verify the color identified by thesystem and displayed on the customer’s monitor 6. These functions may beprovided by either server side programs (via the Common GatewayInterface) which accept the information input by the customer or by aclient side applet (e.g., Java), which is a program downloaded to aclient that executes in the customer’s computer environment.

In one aspect of the invention, the server can handle numeroussimultaneous requests. The server can pass the customer information andselected ink formulation information to a manufacturing facilityselected by the server according to established guidelines. Theguidelines may include, for example and without limitation, proximity tothe customer’s print shop, whether the manufacturing facility has thenecessary materials for the ink formulation in inventory or will havethose materials in time to meet the customer’s needs, and capacity ofthe manufacturing facility.

The second computer 10 (illustrated as the server) selects an inkformulation and transmits the color data associated with the selectedformulation to the first computer 4, where the color of the selected inkformulation can be viewed on color monitor 6 and approved by thecustomer at the remote location. The color of the selected inkformulation can be viewed under different lighting in the viewing booth8, for example daylight D65, cool white fluorescent, and incandescentlighting.

The server 10 uses three software packages, 12, 20, and 22, to select anink formulation to match the desired color. Software package A 12 movesinformation back and forth between other components of the system.Spectrophotometer 14, color monitor 16, and viewing booth 18 are used intwo ways. First, they are used create a color database associated with aset of ink base colors for manufacturing the ink, or for modifying orupdating the database to reflect changes or additions to the ink basecolor set. Secondly, they are used for monitoring the results of the inkcolor selection so that the manufacturer can view the same results seenby the person at the remote location.

Software package B 20 converts the spectral data of a color that isinput from the computer 4 or the database software 22 to the digitalinformation that will produce the same color on the screens of monitor 6and 16.

Software package C 22 includes a database of color information for theink base color set that will be used to manufacture the ink. Softwarepackage C 22 uses the database information to select an ink formulationthat will produce a printed ink having the closest color match to thedesired color, within any other parameters specified. Other parametersthat the software C 22 may take into account include selection of aleast expensive formulation having no more than a specified colordifference (E compared to the desired color, selection of a formulationthat will have a given chemical resistance, selection of a formulationusing on light-fast ink color bases, and so on. Basically, colormatching involves duplicating, as closely as possible for given formulaconstraints, the spectral curve for the color in the visible lightspectrum of 400 to 700 nm. The color matching is described in moredetail below.

When the selected color has been approved by the customer at the remotelocation, the customer can send the approval from computer 4 to theserver 10 for manufacturing the ink. The server 10 then transmits theformulation data to the automated dispensing equipment 24. The automateddispensing equipment 24 dispenses and mixes the ink color basesdesignated in the ink formulation to produce the ink. The ink is thenpackaged and shipped to the printer.

In a first step of the process, the printer-customer inputs informationabout the desired printing ink needed and other information that may berelated to ordering the printing ink. Although the information could besent by the customer through other means, such as telephone ortelefacsimile, to be entered into the second computer or server, theinformation is preferably input via a graphical user interface by thecustomer and transmitted from the first computer (client) to the secondcomputer (server). One example of an interface for entering informationis shown in FIG. 2. The information input by the customer includes thespecific color needed and the identity of the printer, and preferablyalso includes the identity of the print buyer for which the printing isbeing done. Additional information regarding an order of the ink mayalso be input, for example the volume of ink needed, mode for shipping,the customer’s location, and the customer’s authorization of payment.

It is especially preferred to include additional information relating tothe print substrate, printing equipment, and other information that mayaffect the color match on the substrate or performance of the ink.Examples of such information include, without limitation, type ofsubstrate, color of substrate, print process (e.g., offset, gravure,sheetfed, flexographic, etc.), type of printing equipment, press speed,and/or type of ink or ink properties desired (e.g., UV curing, chemicalresistant, solvent based or water based, air dry, heatset, etc.).

It is also possible to input information from two or more separatelocations. For instance, the color spectral data can be obtained andinput at one location and other information can be input from a secondlocation, so long as the information from both locations is identifiedas belonging to a single order file.

A variety of methods for inputting the desired color is envisioned. Inone embodiment, the desired color may be input as appropriatecoordinates of a color space. The color coordinates can be obtainedspectrophotometrically for example using a reflection spectrophotometer,and expressed in coordinates such as the color coordinates such as X, Y,Z or L*, a*, b*, or in cylindrical coordinates r, (, l or L*, C*, H*..The color coordinates can be input directly from the spectrophotometer,entered by a keyboard, using a mouse or track ball, or otherwise.Although the color can be measured using other instruments, such as acolorimeter, such methods are more limited and more accurate colormatching can be obtained using a spectrophotometer.

In a second embodiment, the color can be selected from a library ofcolors shown on the customer’s computer monitor. The customer can selectpotential colors by using an electronic input device. Any electronicinput device can be used in connection with the appropriate software,including, without limitation, keyboard, mouse, track ball, light pen,electronic tablet, touch screen, voice recognition device, and so on.The colors may be shown as an array of color chips or boxes, as acontinuum of colors such as a color space, or in any other suitable way.For example, the color may be selected from the colors that can bedisplayed by a monitor, with the digital identity of the selected colorbeing transmitted for color matching to the component of the inventionthat determines the ink formulation for the closest color. In onepreferred embodiment, the chosen color occupies a larger portion of theviewing area in a new screen so that the customer can compare theselected color to a color standard and verify the color choice.

In a third embodiment, the desired color is input by scanning in a colorstandard using a scanner with accurate color reproduction capabilities,by photographing the color with a digital camera, and so on. The inputcolor may be displayed on the terminal screen.

In yet another embodiment, the desired color can be specified byreference to a color in a color guide or swatch book of differentcolors, such as the color guide published by Pantone, Inc. of Carlstadt,N.J. in the Pantone® Color Formula Guide. A database containing colordata defining each color can be accessed, and the color data for thespecified color may then be used as before to determine the formulationwith the closest matching color for the given set of ink color bases.

In a variation of the process, a customer can input a code assignmentfor a color that has already been matched. Thus, once a print buyerselects a color, the color is matched and assigned a unique code thefirst time it is used in the process, and thereafter the same color maybe selected (by the first printer or by any later printer) by inputtingthe unique code only without further color matching steps.

In making a color match, the server accesses a color match routine toproduce an ink formulation of the specific color. The color matchroutine compares the color information input from the customer to thecolor information in a database containing data for the ink base colorsfor ink color bases from which the ink will be prepared and selects theproper proportions of the ink color bases to achieve a closest colormatch. The database is prepared by measuring the color information forprint samples prepared from the ink color base set and/or combinationsthereof at different concentrations or strengths. The database containsa sufficient number of color information points so that the computer canextrapolate, if necessary, the color information that would result fromthe different combinations of the ink base color set. In other words,the computer calculates a synthesized spectral curve or other colorinformation for the ink formulation based on the color information forthe different concentrations of each ink base color.

The color information used to prepare the color matching database can beobtained by the proofing procedures typically used for inks, such aswith the use of an IGT proofer, measuring the color informationpreferably with a reflection spectrophotometer.

In general, color matching can be carried out in different ways, withsome ways capable of providing more accurate results. First, the secondcomputer can compare the spectral curve in the visible region of thedesired color to the spectral curves of possible ink formulations andselect the ink formulation or formulations having spectral curvesclosest to that of the desired color. The comparison can be done usingstandard curve fitting techniques, for example least squares fit. In asecond color matching technique, the desired color can be expressed incoordinates in color space, such as CIE coordinates L*a*b*, L*C*H*, orL*u*v*. When the color coordinates are used in color matching, anestablished color tolerancing method can be used to calculate the colordifferences between two points. CIELAB is one common color tolerancingmethod that calculates the color difference (E as

(E=Sqrt[(a₁*-a₂*)² +(b₁*-b₂*)² +(L₁*-L₂*)²]

In the CMC tolerancing method, the color difference (E is calculatedusing an ellipsoid around the standard color with semi-axescorresponding to hue (S_(H)), chroma (S_(C)), and lightness (S_(L)):

(E=Sqrt[(L*/lS_(L))² + ((C_(ab)*/cS_(C))² + ((H_(ab)*/S_(H))²]

with the lightness factor l being 2 and the chromaticity factor cbeing 1. An example of a program for comparing a desired color todetermine optimum color match is the COLORITE brand color matchingsoftware of Datacolor, Lawrenceville, NJ. The CIELAB color coordinatescan be computed from a full reflection spectrum using formulas publishedby CIE (Commission Internationale de I'Eclairage). Instruments such asthe X-Rite 938 spectrodensitometer available from X-Rite, Grandville, MIalso exist which directly provide CIELAB coordinates.

Because print color can appear different when viewed under differentlight sources, it is preferred to include in the database colorinformation for the colors as they would appear under different lightsources, for example in sunlight, in D65 Daylight, cool whitefluorescent light, and incandenscent light. The color information of thedesired ink color can then be input for each of the different lightsources, and the color match can be made by determining the lowest (Ewhen taking into account the color of the ink for all of the differentlight sources.

The color match can also be determined by the comparison of thereflectance values in the visible spectrum for the desired color and thecolor identified by the color matching program. A least squarescalculation can be done to determine the ink formulation that will havethe spectral curve with the closest fit to the spectral curve of thedesired color standard, where the spectral curve for the ink formulationmay be extrapolated from information of measured spectral curves in thedatabase.

The color of the selected formulation can be displayed on the customermonitor for approval by the customer. In this context, the “customer”can be the printer and/or the print buyer and/or a designer of packagingor other printed media. For example, the color of the selectedformulation can be displayed on a half-block next to a half-blockdisplaying the color input by the customer or in a color window shown onthe monitor screen with other data. One example of such a screen isshown in FIG. 3. In approving a color, the customer can compare thedesired color and the selected ink color shown on screen under each ofthe different light sources. Alternatively, the second computer cantransmit a display showing how the desired color and selected ink colorwill compare under different lighting conditions.

In order for such a display to be successful in showing the results of athe calculation of a color match for the ink color base set, the displaymust be able to faithfully reproduce the colors. It is known how tocalibrate the colors on a monitor to accurately display the selectedcolors on the monitor. Commercial calibration systems are available, forexample, from X-Rite, Inc., Grandville, MI and from Datacolor,Lawrenceville, NJ. Generally, such calibration involves using standardtiles with known reflectance values.

In the same way, the results of the color matching process can be sentto the customer in different forms for color approval. First, the colorof the selected ink formulation and the desired color can be displayedside by side on the monitor. The color monitor 6 must be properlycalibrated so that it accurately displays the color of the selected inkformulation and the desired color that is being matched. The colorsdisplayed on the color monitor 6 can be viewed under different lightingby employing the viewing booth 8 with variable lighting. Alternatively,the second computer 10 can electronically calculate how each color wouldappear under the selected different lighting, and send to the firstcomputer results that display the desired color and the color of theselected ink formulation for each of the lighting conditions selected.

The customer can approve the color shown or request that the color bemodified. For example, the customer can send a request back to the colormatching program requesting that the color be made lighter, and thenview the results of that request. The results can be returned to thecustomer for viewing and approval within minutes, as compared to thedays that it takes to manually prepare a new ink color, print the ink ina proof, and deliver the proof to the customer.

Alternative criteria can be established to select an ink formulation tomeet the printer’s or print buyer’s needs. For example, instead ofselecting the closest color match possible, the system can determine thelowest cost formulation that has a reasonably close color match,specified as a certain (E. A closest color match can also be determinedusing color bases having certain properties. For example, a set orsubset of color bases can be used to produce an ink with propertiesselected from inks chemical resistance, lightfastness, radiationcurable, heat resistance, foil stampability, UV-coatable, laserimprintable and combinations of these. The information input along withthe desired color can include whether such specific property is neededin the ink. If a certain property such as chemical resistance isspecified, then the system of the invention uses only those ink colorbases designated for that property in determination the ink formulation.

The ink formulation identified with the input color can be saved in adatabase in connection with the print buyer information supplied by thecustomer, the customer’s identity and order information, date ofapproval by the printer, print buyer, or designer, or other information.

In the case in which a formulation has been identified for a first typeof ink, for example an offset ink, and the same color is desired for asecond type of ink, for example a gravure ink, the color data for thefirst type of ink is the desired color and the same process is followedfor determining a formulation for the second type of ink using base inkcolors of that type of ink.

Additional information can be input to the program that determines thematching formulation to assure color match and ink performance for thespecific printing job. It is known, for example, that color can vary foran ink depending upon the substrate being printed. For example, an inkmay appear to have a different color when printed on a colored substrateas compared to a white substrate, or when printed on a different gradeof paper, when the stock is coated as compared to uncoated, the desiredthickness of the print layer, or when printed on a plastic or metalsubstrate as compared to paper. The calculation of the formulationpreferably takes into account the color shift, if any, expected for thesubstrate being printed. The types of parameters than may be taken intoaccount in the calculation of the formulation may include, for exampleand without limitation, substrate type, substrate color (which may alsobe input as spectral data or selected in any of the ways alreadydiscussed in connection with inputting the desired ink color),absorption of the substrate, paper weight when the substrate is paper,whether a paper or paperboard substrate is coated or uncoated, and soon.

The identified ink formulation is then transmitted to manufacturingequipment. The manufacturing equipment may include, for example, anautomated dispensing system that dispenses the correct amount of eachbase color in the ink formulation to make an ink. The automateddispensing system may be connected electronically to the program thatreceives the customer’s data and determined the correct ink formulation.The dispensing system may also be controlled by inputting information byhand, such as through a keyboard. The manufactured ink is then shippedto the customer.

The system may include further components related to manufacturing, suchas labeling software, inventory software, and financial software. Suchcomponents are known in the art and need not be described further.

By using the system of the invention, the time needed to match acustomer’s color, produce an ink of the correct color, and ship the inkto the customer is greatly reduced over the current process in which thecustomer sends a color sample to the ink manufacturer, who develops aformula for an ink that matches the color of the sample, and finallymanufactures the formula and sends the ink to the customer.

In one preferred embodiment, the system provides inks for offsetlithographic equipment, including sheetfed printing equipment and webprinting equipment, although the invention can be applied to inks forother types of processes, such as gravure, flexography, and silk screenprinting processes. The ink can be radiation curing (including UV curingand electron beam curing), air dry, cold set (absorption inks such asnewsink), heat set, waterborne, or solventborne inks.

For example and without limitation, a base color set used to producelithographic inks may include a set of different ink colors having thesame varnish or vehicle system that can be blended to yield a wide rangeof colors. The base color set typically includes at least about twelvebase colors and may include 40 or more base colors. While increasednumbers of base colors increase the complexity of the dispensing andmixing system, increased numbers of base colors also enhances theability of the system to closely match customer colors and to meetcustomer demands for specific ink properties such as light-fast colors,heat resistant colors, and chemical resistant colors.

In a preferred embodiment, the varnish for the base color set ispreferably selected for good printing characteristics on a variety ofprinting presses.

In another embodiment of the invention, the viscosity or otherproperties of the color-matched ink can be adjusted to suit a particularprinting press, for example by adjusting the additive package in the inkor by adjusting the ratio of different varnish resins in the ink. Suchadjustments can be made depending upon press design and configuration,type of fountain solution or printing plates in lithographic printingprocesses, and so on.

Many kinds of printed materials may be made by the process of theinvention, including informational and sales brochures, insertadvertisements, magazines, catalogs, company financial statements andannual reports, packaging materials including cartons, other containers,and labels, and so on.

The invention has been described in detail with reference to preferredembodiments thereof. It should be understood, however, that variationsand modifications can be made within the spirit and scope of theinvention and of the following claims.

1. Cancelled.
 2. Cancelled.
 3. Cancelled.
 4. Cancelled.
 5. Cancelled. 6.Cancelled.
 7. Cancelled.
 8. Cancelled.
 9. Cancelled.
 10. Cancelled. 11.Cancelled.
 12. Cancelled.
 13. Cancelled.
 14. Cancelled.
 15. (NEW) Asystem for providing a formulation that will produce a color matching adesired color, comprising: a first computer that can communicate with asecond computer, said first computer comprising (a) a database forpredicting color produced by formulations prepared using a set ofmaterials; (b) a color matching program for using the database tocalculate a formulation that will produce a predicted color matching thedesired color; (c) a software program for sending information to thesecond computer to display the predicted color on a color monitorconnected to the second computer.
 16. (NEW) A system according to claim15, wherein the software program of (c) can send information to thesecond computer to display the desired color on the monitor along withthe predicted color.
 17. (NEW) A system according to claim 16, whereinthe software program of (c) can send information to the second computerto display how the predicted color and the desired color would appearunder different lighting conditions.
 18. (NEW) A method for making anink with a print color matching a desired print color, comprising stepsof: receiving with a first computer color information for the desiredprint color from a second computer; accessing with the first computer adatabase for predicting print color for ink formulations; accessing withthe first computer a color matching program to select an ink formulationhaving a print color matching the desired print color.
 19. (NEW) Amethod according to claim 18, wherein said first computer and saidsecond computer are connected by a global communication network. 20.(NEW) A method according to claim 18, further comprising steps ofproviding the ink formulation to automated manufacturing equipment andmanufacturing an ink according to the ink formulation.
 21. (NEW) Amethod for modifying an ink formulation, comprising the steps of: (a)inputting to a first computer a desired color change for a print colorof a first ink formulation; (b) accessing with the first computer acolor match program to produce a second ink formulation having a printcolor with the desired color change; (c) transmitting to a secondcomputer display data to display on a monitor the print color of thefirst ink formulation and a print color of the second ink formulation.22. (NEW) A method for comparing a print color to a desired color,comprising transmitting from a first computer to a second computerdisplay information to display on a monitor the print color and thedesired color.
 23. (NEW) The method according to claim 22, wherein thedisplay data includes data to display the print color and the desiredcolor as they would appear under at least two different light sources.24. (NEW) A method of formulating ink, comprising steps of: inputting toa first computer data for a desired print color and at least oneparameter selected from the group consisting of: ink properties, type ofink, cost, printer identity, printing process parameters, pressequipment parameters, press speed, substrate type, substrate color, andcombinations thereof; accessing with the first computer information forpredicting print color for ink formulations using a set of ink basecolors selected based on the at least one further parameter, using acolor matching software program to select an ink formulation for the atleast one further parameter having a desired match to the desired color.25. (NEW) A method of providing two ink formulations, comprising stepsof: selecting a first ink formulation by the method of claim 24 andselecting a second ink formulation by the method of claim 24, whereinthe desired print color is the same for the first ink formulation andthe second ink formulation and further wherein at least one parameter isdifferent for the first ink formulation and the second ink formulation.26. (NEW) A method according to claim 25, wherein the predicted printcolor for the first ink formulation has no more than a specified colordifference compared to the predicted print color for the second inkformulation.
 27. (NEW) A method according to claim 25, wherein the firstcomputer transmits to a second computer display data to display on amonitor the print color of the first ink formulation and the print colorof the second ink formulation.
 28. (NEW) A method according to claim 27,wherein the first computer further transmits to the second computerdisplay data to display on the monitor the desired color.
 29. (NEW) Amethod according to claim 25, wherein the at least one parametercomprises type of ink.